Vacuum tube



April 17, 1.928.

W. A. RHODES ET AL vAcuUM TUBE Original Filed Sept. 5, 1925 mvzmons pa es j I y ATTORNEYS Patented Apr. 17, 1928.

, UNITED STATES PATENT, OFFICE.

WILLIAM L moons Ann DAVID BELLAB, or BROOKLYN, NEW YORK.

vacuum TUBE.

Application filed September 3, 1925, Serial No. 54,292. Renewed February 25, 1928.

This invention relates to an improvement in vacuum tubes.

An object of the invention is to provide a vacuum tube which has a capacity for amplification and detection which is superior to those now in use.

A further object concerns a construction of a tube which is provided with means for acting not only as a detector but a multistage amplifier.

A further object concerns the provision of a tube in which a single tube having one filament can be used in place of a plurality of tubes in a multi-stage radio set.

A further object concerns the provision of a tube which is simple, strong and capable of handling muchlarger filaments and plate voltages and currents than has hitherto been possible.

The invention is illustrated in the drawings of which Figure 1 is a side elevation partly in section of a simple form of our tube;

Figure 2 is a section through a form of our tube in which a plurality of stages are used Figure 3 is an inverted plan view of the base of the tube shown in Figure 2;

Figure 4 is a diagram of a circuit in which our tube can be used.

The form of the invention shown in the drawings in a preferred form, although it is understood that modifications in the construction and arrangement of the parts and in the character of the materials used may be adopted without departing from the spirit of the invention as set forth in the appendedclaim. 4

. The referred form of the invention as shown in the drawings comprises a bulb 10,

and a base 11, provided with the usual terminal pins 12 to 15 inclusive, Within the bulb 10, which is evacuated to a high degree,

is a glass stem 17 "from which rises a glass tube 18 having a lateral opening 19. From the top of the tube 18 a. wire 20 is bent to support a glass bar 21. From this glass bar 21 are supported a plate 22, an outer grid 23 and an inner grid 24. These elements are connected respectively by wires 25 26 and 27 to terminals 12, 13 and 14.

A wire 28 a filament 2.9 with the ber C.

wire 27. Theother end of the filament 29 is connected by a wire 29 to the terminal 15.

The filament is disposed within the tube 18. As the filament 29 is heated the ionic emission will pass through the opening 19 and bombard the plate 22 passing through the grids 23 and 24. The inner grid 24 being located nearest the filament and being connected thereto will affect the plate current by induction. It is found that this form of tube has 'a much greater amplifyin power than the standard tube and wil stand higher voltages and currents without damage.

Figure 2 shows a bulb 30, having glass artitions 31 to 35inclusive se aratlng the ulb into,five chambers A, B, 8, These partitions on their inner ends connect to a central glass tube 36 within which is dis osed a filament 37 This tube 36 is provi ed with openings such as 38 leading to respective chambers above mentioned. In each of the chambers above mentioned are located a. plate 39, an intermediate grid 40 associated with the one filament 37,. In a manner similar to that shown in Figure 1,

all the inner grids 41 are connected to one side of the filament 37 D and E.'

In Figure 3 we show the ba'sebf the tube, shown in Figure 2, and it is provided with twelve terminal pins. The pins 42 and 43, for instance, are connected to the respective ends of the filament 37, one of said pins, 42, for example being also connected to the five inner grids 41. The terminals 44 and 45 are'connected to the intermediate grid 40 and the plate 39 in chamber A. The terminals'46'and 47 are connected to the intermediate grid and the plate in chamber .B. The terminals 48 and 49 are connected to the intermediate grid and-Lplate in cham- The terminals 50 and 51 are connected to the intermediate in chamber D and the terminals 52 and 53 are connected to the intermediate grid and platein chamber E. i

One tube of the character shown in Figure 2 can be used as a. detector and an amplifier for four stagesv of amplification, either audio oi rad o frequencies.

grid and plate In Figure 4 we show m circuit in which our tube can be used. In this case the tube would require only three chambers What. we claim is A vacuum tube comprising a bulb and a base, having a high vacuum in the bulb, a.

) filament, a-plate and intermediate grid, and

an inner grid disposed within the bulb, the 

